Question

Describe K⁺ transport stomatal mechanism.

Answer 1

According to the theory the change in turgor pressure that open and close the stomata results from the reversible absorption and loss of potassium ions (K⁺). Light-induced stomata opening is accompanied by transport of K⁺ from subsidiary cell to the guard cells. It is an energy-requiring process.

During day, starch produced change into malic acid which dissociates in malate anions and H⁺ in guard cell H⁺ is exchanged with K⁺ in subsidiary cells. It is active process. K⁺ ions and malate ions results in increase osmotic pressure and water moves into guard cells from surrounding cells. Increase in turgor results in opening stomata.
During the night, the reversal of K⁺ – K^– pump, low osmotic pressure of guard cell, inducing closure of stomata through exosmosis.